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I'm starting a thread here on putting Ford pushrod 302's into various of our locosts. I have something that at least occupies the space of a 302 engine, I need help to get it running and it's complicated some because I want to run it on the Engine Control Unit that I am designing and building.

The motor I have uses a distributor and I expect to upgrade it to individual coils or wasted spark. So I will get a "cam position sensor assembly" which replaces the distributor and it's geared shaft with something with a little sensor instead. This motor also has no provision I see for crank position. I do have a trigger wheel I will chuck in my drill press for some testing at low speed I want to do.

http://www.summitracing.com/parts/rnb-689-103/overview/make/ford/model/explorer

Can anyone describe and or provide a picture of what their motor uses for a stock trigger wheel?

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
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There is a company I just asked my buddy about via text.. he converted to a COP ignition system, and bought a crank dampener with a trigger wheel built into it. The cam position sensor mounted using one of the timing cover bolts and a small bracket. I think it cost him somewhere in the area of $250.

I'm only posting so I remember to pester him if he doesn't remember to answer me and I forget.

He said this is the one.. http://electromotive.com/our-products/f ... igger-kit/

he used it with a megasquirt with success

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Tucker

OK, I was just looking at my dampener and can see how the big hole in the middle lets it bolt up.

Does this mean there is not a stock trigger wheel? So the Ford Explorer used the cam sensor for a crank sensor too?

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

He said

"I used the electromotive kit because I couldn't get the pulse width of the sensor signal to be usable on my megasquirt with the stock explorer trigger ring"

He continues

"The stock explorer tone ring is something ford specific.. like 26.3 teeth (he couldn't remember exactly) per revolution where as the aftermarket ones are nice easy numbers like 30 or 40. My v2 megasquirt didn't like the decimal point in that box of the program, and wouldn't run well at 26 or 27 teeth per revolution."


I know the later model explorers definitely had a trigger wheel behind the crank, and I think some of the mustangs, maybe only the automatic ones? used a pickup on the flexplate.

I honestly don't think I've worked on a fuel injected, HO mustang 302, or done any work down there by the crank to notice. a quick google search shows conflicting information.

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Tucker

Marcus, maybe you need to get in touch with James over at Slotus Central!

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Mike - Read my story at http://twinlakesseven.blogspot.com/

Yup, I did just that... James sez that the EEC-5 equipped Explorers and Mountaineers from about 1996 up had a trigger wheel on the crank. 1997 and up F-150s had the same setup. The cam sensor that goes in the distributor drive is used to fire/time the injectors, has nothing to do with the ignition.

Another friend of ours has a 302 with megasquirt, ITB injection and coil-on-plug ignition. I'll talk with him tomorrow about what kind of trigger(s) he uses. I know the coil units are GM, but beyond that I'm not sure.


JDK

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JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

I knew you could hook him up, JD!

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Mike - Read my story at http://twinlakesseven.blogspot.com/

OK, thanks for asking James. If the cam sensor on those motors isn't needed for the ignition that means it's using 4 coils in wasted spark. That's fine and it means there are OEM sensors, trigger wheels, coils and mounting hardware.

We'll have to look into how many teeth the stock wheels have. 1055, I don't know how a wheel can have a fraction of a tooth? I hope we can use stock parts for this type of thing because in general it will save money.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Get a universal trigger wheel Marcus, much cheaper than buying bolt on kits. If you sandwich the wheel between the crank pully and the damper you can then tease the pulley mounting boss on the waterpump forward a tad with a puller to keep all the belts in line.

http://trigger-wheels.com/store/

Bob

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Build Log viewtopic.php?f=35&t=16640&p=187700#p187700

Mancave http://s1116.photobucket.com/user/mypic ... ow/mancave

Its not a fraction of a tooth, but the teeth are spaced as such that one tooth overlaps the revolution, if that makes sense. or it splits the 0° mark on the crankshaft itself.


Edit: I just called him, because he wasn't making sense via text.

He looked at his notes, the stock explorer wheel is a 36-1 trigger wheel, with a missing tooth, so that the engine knows where the crank is. The problem that he ran into, and there is probably a way around it, is that the missing tooth on the crank wheel is at 50° from the 0° timing mark.. the 0° timing mark is not at 12 noon on those motors, and his mega squirt did not like the missing tooth, or offset pickup location, or some combination of the both.. so he ditched it for the universal pickup, then synced the crank signal to the cam signal he already have. Used the crank signal for spark, and cam signal for injector pulse.

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Tucker

I'm thinking out loud here. Without a cam sensor, you won't be able to run sequential injection, right? Batch injection would work, but not as efficiently. Maybe I'm thinking it wrongly.

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Chuck.

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The 36-1 trigger wheel used on most fords works fine with the Megasquirt computer, you just have to specify the offset of the missing tooth from TDC on #1. You can probably make it work with your computer as well, as long as you can filter a variable reluctance signal. EDIS uses different offsets for different engines, so on a 4 cyl engine the missing tooth will be 90* ahead of TDC, whereas on V6 and V8 engines it will be less. While I used EDIS on my build, the same crank wheel can be adapted to work with a standalone computer that drives spark as well. The crank sensor and cam sensor on my donor vehicle are both variable reluctance sensors, with the cam sensor simply reading a split lobe directly on the camshaft (basically a half circle instead of a cam lobe, where half the circle is cut out to give a nice sharp edge for the VR sensor to read). The crank trigger wheel I have is cast directly into the crank pulley/harmonic balancer. It's about a 6" diameter, 1/4" thick steel, though I've seen much thinner ones made to work with VR sensors. Mine is from a 93 Escort and I had to bore out the centre hole and file in a new key notch to get it to fit on the motor I'm running. For your cam position you could have just a single notch sticking out on a dummy distributor shaft that the VR picks up.

Thanks for all the help guys.

On these motors I think the cam position is just used to let you know if you are on a compression or exhaust stroke. Remember we only fire every other revolution, so we need the information from the cam which is running at half speed. If you have a coil for each cylinder I think you could fire the coils twice as often at startup, then after it starts you could drop one ignition pulse and learn which stroke you're on and go from there. Once you know this, it shouldn't change until you forget where the crank is after you turn off the engine.

We do have an OEM cam sensor though. Since it's replaces the distributor, cleans up the engine and makes it smaller - not to mention drives the oil pump, it seems to make sense to use it. They are reasonable price and from what I read the Motorcraft one is better than the common Dorfman one.

Here is the crank sensor from Summit: http://www.summitracing.com/parts/smp-pc325/overview/make/ford/model/explorer

It's listed as for Explorer.From picture on the net it looks like it mounts to the engine front cover at about 10 or 11 o'clock looking at the front of the engine. Still not clear what the actual gear looks like. My front cover doesn't seem to have those bolt holes though, too bad.

I'll look at the universal parts too, thanks bob.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Yup, that's a standard variable reluctance sensor. You can find them on many different fords in the junkyard, in different mounting eye arrangements. The one I'm using for the crank sensor has a dual eye mounting like the one you showed, whereas the cam sensor has a longer shaft to go through the valve cover, and a single eye mounting on the rear. I made a little bracket to hold the sensor which bolts on to the motor using a couple of the oil pan bolts. I can take a picture of it tomorrow evening, but it's pretty straightforward.

The output of a VR sensor is a variable voltage with a peak when you transition from having no metal to some metal close to the sensor, and a zero crossing when the distance from the metal is constant. The trigger wheel could look any way you want it to really, as long as you have some parts that pass close to the sensor (1-2mm distance) and some that are farther away, with sharp transition between them. The 36-1 wheel is nice since each tooth is spaced 10 degrees apart on the wheel, giving you lots of resolution if you have a fast timing circuit, and the missing tooth gives you a position reference within the rotation. Then, as you say, the cam sensor just tells you which half of the 720 degree cycle you're on. If you have a steel crank pulley you could just cut notches in it to act as the trigger wheel (VR sensor needs a ferrous trigger wheel).


Edit:
For reference, this is the crank sensor I'm using:
http://www.rockauto.com/en/moreinfo.php ... 04&jsn=868
And this is the harmonic balancer with trigger wheel built it:
http://www.rockauto.com/en/moreinfo.php ... 51&jsn=851

I was hoping for a nice OEM part or combinations of parts. It's a whole subject though including harmonic balancers, timing covers, water pumps, dipstick and maybe other stuff I haven't thought of yet.

I think Summit lists a dozen timing covers for these engines but I don't know enough about the wider picture of what the different models mean. We don't need the fuel pump port. It's not clear wether the ones that support a crank sensor are for the actual street sensors or include the ability to use generic racing parts. I was looking at Ford Explorer parts but the Crown Vic and Lincoln parts might be more suitable or different.

Can someone post pics of their timing cover, left side ( Gonzo or Trochu especially )?

I am pretty comfortable with the signal side of this. A friend lent me a generic timing wheel and VR sensor.Here's what the signal looks like with the parts setup in my drill press at about 550 RPM. I'm doing this part of it because I'm testing circuits for the ECU project.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.